The invention relates in general to wells and in particular to initiating flow from a well.
To initiate the flow of oil and/or other materials in a well, a conventional shaped charge warhead (or perforator) is fired through the well casing, the cement sheath and into the earthen formation. A shaped charge device comprises a shaped charge liner backed by high explosives. When the explosives are detonated, the shaped charge device forms a high velocity forward moving penetrator or “jet” that is capable of deeply penetrating the targeted material.
Output of a well is dependent on several factors including the size of the hole made by the perforator, the hole shape and the penetration depth. Fracturing fluids are pumped into the hole to fracture the rock formation and special agents in the fluid hold the fractures open to allow flow. Small diameter holes (as produced by conventional shaped charges) have a tendency to clog with these agents. Well and rock conditions vary at different depths in the same well and in different wells, due to geological differences.
A variety of perforators are available for different applications. A disadvantage of conventional perforators is they can only produce one jet profile per design. A single perforator lacks the ability to handle varying well and rock conditions. Most available perforators are designed to produce deep penetration but with a very small diameter hole. To change the jet output and, therefore, the hole profile, a different perforator is required for each desired hole profile.
At present, a variety of perforators must be on hand to handle different situations. U.S. Pat. No. 6,925,924 issued on Aug. 9, 2005 and is incorporated by reference herein. The '924 patent shows shaped charge perforators with multiple initiation points. These perforators can produce different jets. However, each perforator is limited to producing a single jet profile. Thus, a need exists for a single perforator that can selectively produce varying jet outputs for different applications.